#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>

void DefStrcat(char* a, const char* b)
{
	while (*a)
	{
		a++;
	}
	while (*a++ = *b++)
	{
	}
}

int main()
{
	char a[10] = "abcdef";
	DefStrcat(a, "hig");
	printf("%s", a);
	return 0;
}